Hi I used to get really stressed out during exams and I found some essential oils actually helped a bit. Lavendar is good for calming and rest at night and peppermint is good for boosting the brain. You could also get an oil burner for her.
Also does she listen to music when she works or the radio.
Some nice coffee and tea.
Some lovely bubble bath to relax in after a hard night's studying.
Hope that helps